Millions of Muslims in Iran and across the world will celebrate the birth anniversary of Islam’s holy Prophet Muhammad (PBUH).

The Prophet of Islam (PBUH) was born on the 17th day of the lunar calendar month of Rabi’al-Awwal in about 570 AD, in the Saudi Arabian city of Mecca. This year, the day falls on December 6.

The birth date of the Prophet Muhammad (PBUH) coincides with that of Imam Jafar Sadiq (PBUH), the Sixth Shia Imam.

According to the Sunni narrative, the birth date of the Prophet (PBUH) falls on the 12th of Rabi’al-Awwal. According to a call made by the late Founder of the Islamic Republic, Imam Khomeini, the week in between the two dates is marked each year as “Islamic Unity Week” to promote convergence among Muslims.

In addition, the 28th day of the month of Safar (the second month in the lunar calendar) marks the passing away of the Prophet Muhammad (PBUH) as well as the martyrdom of his grandson Imam Hassan (PBUH), the second Shia Imam.

Muslims believe that Islam is a faith that has always existed and that it was gradually revealed to humanity by a number of prophets. At the age of 40, Muhammad (PBUH) was ordained to be the final prophet by Allah. After 23 years of disseminating the message of Islam, the Prophet passed away at the age of 63.

Muhammad’s first revelation was an event described in Islam as taking place in 610 AD, during which the Holy Prophet (PBUH) was visited by the Archangel Gabriel, who revealed to him the beginnings of what would later become the Holy Qur’an.

The revelations (each known as Ayah, lit. “Sign [of God]), which Muhammad (PBUH) reported receiving until his death, form the verses of the Qur’an, regarded by Muslims as the “Word of God,” around which the religion is based. Besides the Qur’an, Muhammad’s teachings and practices (Sunnah), found in the Hadith and Sira literature, are also upheld by Muslims and used as sources of Islamic law.